Memory card with write protection switch

ABSTRACT

A memory card and apparatus used therewith. The memory card comprises a rectangular card body having terminals in the vicinity of one end and a storage device disposed in the card body for storing data. A switch on the card is operable to a state to prevent stored data from being erased; and a status signal representing the state of the switch is supplied to one or more of the terminals. The apparatus with which the card is used has mating terminals to receive the status signal. Depending upon the state of that status signal, the apparatus is selectively inhibited from writing data to the memory card or erasing data stored in the memory card.

This is a Continuation-in-Part of application Ser. No. 09/088,590, filedJun. 2, 1998, now U.S. Pat. No. 6,109,939; and application Ser. No.09/086,788, filed May 28, 1998, now U.S. Pat. No. 6,170,743.

FIELD OF THE INVENTION

The present invention relates to a memory card designed for reception ina memory card receptacle and into or from which information is writtenor read, the memory card having erasure prevention.

DESCRIPTION OF RELATED ART

A well-known memory card incorporating memory chips in which informationsignals are stored is provided with terminals which are to beelectrically connected with an external system. The memory card issupplied with a voltage through the terminals and also delivers andreceives information signals to and from the internal memory chipsthrough the terminals.

Since the terminals for connection of the memory card to an externalsystem are also electrically connected to the internal memory chips,they should be protected from being touched when the memory card isused. More particularly, if the terminals are directly touched, a staticelectricity will take place in them, which although rare, will betransmitted from the terminals to the memory chips, thereby causingdamage. To avoid this, the terminals should be protected against easyaccess from outside.

Also, a desirable feature of the memory card of this type is itstransportability. To design more compact memory cards, thus takingadvantage of their portability, their terminals have been designed to bethinner and closer together.

Such thin, closely disposed terminals for connection to an externalsystem will possibly be deformed and broken even if just lightlytouched.

To prevent the terminals from being deformed or broken, it has beenproposed to bury such terminals inside the memory card body and smallholes communicating with the terminals are formed in the memory cardbody so that the terminals are exposed only through the holes. Inanother proposal, a concavity is formed in a forward, or leading, endportion of the memory card body and terminals are disposed in the bottomof the concavity where they are protected.

However, the memory card in which the terminals are exposed throughsmall holes is difficult to disconnect from a receptacle therefor if theholes are clogged with dust or the like. When the memory card isinserted into the receptacle with clogged holes, no positive connectionwith the receptacle can be attained and also the terminals of thereceptacle may possibly be deformed.

Further, the above memory card is apt to have a complicated structureand is expensive to manufacture. Therefore, this type of memory card isnot suitable for mass production.

Also, in the memory card having a concavity in the body in which theterminals are disposed, the terminals cannot be satisfactorily protectedif the concavity is improperly shaped. For example, dust or the like islikely to heap or stay in the corners of the concavity and block theterminals of the memory card from secure connection with the terminalsof the receptacle.

As a data storage device, the memory card should have an erroneous eraseprevention switch for preventing erroneous erasure of data storedtherein. However, if the erase prevention switch is provided on a mainplane of the memory card body, a user cannot operate the switch when thememory card is mounted in the receptacle of an electronic apparatus. Forexample, if the memory card is inserted into an electronic apparatus andthe user finds that the memory card is disabled for writing (that is,erasure is prevented), the user cannot write new data over data alreadystored. The user must eject the memory card from the electronicapparatus, set the erase prevention switch to a write state, and thenre-insert the memory card into the electronic apparatus. This isinconvenient, troublesome and often frustrating.

SUMMARY OF THE INVENTION

The present invention has as an object to overcome the above-mentioneddrawbacks by providing a memory card having a simple structure, adaptedto positively protect the terminals thereof and attain a positiveconnection with a memory card receptacle.

Another object is to provide a memory card capable of preventingerroneous erasure or over-writing of stored data while enabling theerase prevention switch to be set to a desired mode, or state.

The above objects can be accomplished by providing a memory cardcomprising a rectangular shaped body, a concavity open at the top andformed proximate the leading edge of the card body, and terminalsdisposed in the concavity. The memory card has also a projection, orrib, formed in at least a part of the space between adjacent terminalsin the concavity to protect the terminals from being touched from theoutside. The projections define sockets in which are disposed respectiveterminals.

In one embodiment, the memory card according to the present inventionincludes a storage device for storing data supplied from the terminalsby external apparatus, a switch settable to inhibit the writing of datainto the storage device, and a control device for controlling writing ofdata into the storage device.

In the memory card, the switch can be operated even when the memory cardis mounted on or received by the external apparatus; and the controldevice detects the state of the switch when data from the controlapparatus is to be written into the memory card, thereby sending a writeenable signal to the external apparatus when the switch is set to awrite mode, and sending a write disable signal to the external apparatuswhen the switch is set to a write disable mode. For example, theexternal apparatus may include a data store; and when a write enablesignal is received from the memory card, data stored in the data storeis read out and written to the memory card, whereas when a write disablesignal is received from the memory card, read out of the data from thedata store is inhibited.

BRIEF DESCRIPTION OF THE DRAWINGS

The foregoing objects, features and advantages of the present intentionwill become more apparent from the following detailed description ofpreferred embodiments taken in conjunction with the accompanyingdrawings, in which:

FIG. 1A shows the construction of a first embodiment of the memory cardaccording to the present invention;

FIG. 1B shows the construction of a second embodiment of the memory cardof the present invention;

FIG. 2 is a perspective view of the memory card in FIG. 1A;

FIG. 3 is a bottom view of the memory card in FIG. 1A;

FIG. 4 is a perspective view of a third embodiment of the memory cardaccording to the present invention;

FIG. 5A is a plan view of a fourth embodiment of the memory cardaccording to the present invention, showing the essential portionthereof with a shutter member placed to close or cover the concavity;

FIG. 5B is a plan view of the memory card in FIG. 5A, showing theessential portion thereof with the shutter member placed to open theconcavity;

FIG. 6A is a plan view of a fifth embodiment of the memory cardaccording to the present invention, showing the essential portionthereof with a shutter member placed to close the concavity;

FIG. 6B is a plan view of the memory card in FIG. 6A, showing theessential portion thereof with the shutter member placed to open theconcavity;

FIG. 7 is a sectional view of a first embodiment of the memory cardreceptacle according to the present invention;

FIG. 8 is a front view of the memory card receptacle in FIG. 7;

FIG. 9 is a sectional view of the receptacle in FIG. 7 in which thememory card is received;

FIG. 10 is a sectional view of the receptacle in FIG. 7 in which anothermemory card of the present invention is received;

FIG. 11 is a plan view showing the essential portion of another memorycard of the present invention;

FIG. 12 is a plan view showing an example of the shape of the memorycard of the present invention;

FIG. 13 is a sectional view taken along the line X₁-X₂ of the memorycard in FIG. 12;

FIG. 14 is a plan view showing an example of the construction of thereceptacle of the present invention in which the memory card of thepresent invention is received;

FIG. 15 is a sectional view taken along the line Y₁-Y₂ in FIG. 14,showing the example of the construction of the receptacle of the presentinvention;

FIG. 16 is a plan view showing the memory card being correctly insertedin the receptacle;

FIG. 17 is a sectional view taken along the line Y₃-Y₄ in FIG. 16,showing the memory card being correctly inserted in the receptacle;

FIG. 18 is also a sectional view taken along the line Y₃-Y₄ in FIG. 16,showing the memory card correctly inserted in the receptacle;

FIG. 19 is a plan view showing the memory card being incorrectlyinserted into the receptacle;

FIG. 20 is a sectional view taken along the line Y₅-Y₆ in FIG. 19,showing the memory card being incorrectly inserted into the receptacle;

FIG. 21 is a plan view showing an example of the shape of the memorycard of the present invention;

FIG. 22 is a plan view showing an example of the shape of the memorycard of the present invention;

FIG. 23 is a sectional view of the memory card, taken along the lineZ₁-Z₂ in FIG. 22;

FIG. 24 is a plan view showing an example of the construction of thereceptacle of the present invention in which the memory card of thepresent invention is inserted;

FIG. 25 is a sectional view of the receptacle, taken along the lineWI-W2 in FIG. 24;

FIG. 26 is a sectional view showing the memory card being correctlyinserted in the receptacle;

FIG. 27 is also a sectional view showing the memory card being correctlyinserted in the receptacle;

FIG. 28 is a sectional view showing the memory card being incorrectlyinserted into the receptacle;

FIG. 29 is a plan view showing an example of the shape of the memorycard of the present invention;

FIG. 30 is a perspective view showing an example of the shape of thememory card of the present invention;

FIG. 31 is a view of the memory card from a point H in FIG. 30;

FIG. 32 is a view of the memory card from a point I in FIG. 30;

FIG. 33 is a sectional view of the memory card of the present inventioninserted in the receptacle of the present invention;

FIG. 34 is a sectional view of the memory card of the present inventioninserted in the receptacle of the present invention;

FIG. 35 is a block diagram showing a configuration of a host computeraccording to the present invention;

FIG. 36 is a block diagram showing a configuration of a memory cardaccording to the present invention;

FIG. 37 is a flow chart which explains an operation procedure of a hostand the memory card; and

FIG. 38 is a flow chart which explains another operation procedure ofthe host and the memory card.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

A memory card according to the present invention is generally indicatedwith a reference 1.

It is a storage medium which is inserted, for use, into a receptacle ofan external system such as a computer, audio equipment, etc. for read orwrite of information signal between the memory card and external systemthus connected to the memory card. As shown in FIGS. 1A and 1B, thememory card 1 has a card body 2 incorporating a plurality of memorychips 3 such as flash memory, etc. to store information signal, and acontrolling integrated circuit 4 (will be referred to as “controllingIC” hereafter) to write or read information signal into or from thememory chips 3.

Further, the memory card 1 has terminals 5 for connection to an externalsystem as shown in FIG. 2. When the memory card 1 is inserted into amemory card receptacle, the terminals 4 are electrically connected tothose of the memory card receptacle to supply a voltage to thecontrolling IC 4 and transfer information signal and various controlsignals between the memory card 1 and the external system. The memorycard 1 adopts a serial interface and the terminals 5 provided count ninein number.

The card body 2 is a thin, flat, rectangular card made of a syntheticresin, for example. The memory card 1 of this embodiment adopts theserial interface and is designed to have nine terminals 5, and thus thecard body 2 itself is small. As shown in FIG. 3, the card body 2 has ashort side L₁ of which the length is smaller than a half of the lengthL₂ of the long side. For example, L₁ is 21.5 mm while L₂ is 50 mm, andthe thickness of the card body 2 is 2.8 mm.

The card body 2 has an inadvertent erasure—preventive member 6 attachedto the rear end thereof in the inserting direction of the card body 2indicated with an arrow A in FIGS. 2 and 3. The inadvertenterasure—preventive member 6 is engaged on an inadvertenterasure—preventive switch (not illustrated) housed in the card body 2.Sliding the member 6 in a direction perpendicular to the insertingdirection of the card body 2 will turn on/off the inadvertenterasure-preventive switch. Also, the card body 2 has formed on a lateralside thereof parallel to the inserting direction of the card body 2 anarcuate locking cut 7 which prevents the memory card 1 from being freelydisengaged from the memory card receptacle once the memory card 1 isinserted in the receptacle. When the memory card 1 is inserted into thereceptacle, a mating locking projection (not illustrated) provided onthe receptacle is engaged in this locking cut 7 to prevent the memorycard 1 from being freely disengaged from the receptacle.

At one lateral end in the inserting direction, the card body 2 is cut(at 8) obliquely with respect to the inserting direction of the cardbody 2. This cut 8 is formed to prevent the memory card 1 from beingincorrectly inserted into the receptacle. Further, the card body 2 hasformed a concavity 9 formed at the forward end, in the insertingdirection, thereof.

The concavity 9 is formed open to the forward end of the card body 2 andextends longitudinally from the forward end, in the inserting direction,of the card body 2. The concavity 9 is deep a predetermined step fromthe top surface of the card body 2, and thus it is defined by threewalls and a bottom 9 b. One 9 a of the walls of the concavity 9, innerand parallel to the forward open end, is inclined at a predeterminedangle with respect to the bottom 9 b.

Because of the forward open end and inclined inner wall 9 a of theconcavity 9 in the memory card 1, dust or the like in the concavity 9can be easily let out when the memory card 1 is inserted into thereceptacle.

In the concavity 9, there is disposed a plurality of terminals 5 forconnection to corresponding terminals of the receptacle when the cardbody 2 is inserted into the receptacle. The terminals 5 are formed bypunching a thin metal sheet or from a pattern of a printed wiring board.They are laid side by side on the bottom 9 b of the concavity 9 in theinserting direction of the card body 2, and exposed to outside.

Since the memory card 1 of the present invention adopts the serialinterface, the terminals 5 thus provided count nine in number. Namely,the nine terminals 5 disposed in the concavity 9 of the memory card 1include a digital signal input/output terminal, a sync signal inputterminal, a status signal input terminal, four voltage supply terminals,and two reserved terminals.

Further, there are formed between the terminals 5 inside the concavity 9projections 10 serving to prevent an access or touch to the terminals 5from outside. As shown in FIG. 2, for example, the projections 10 extendbetween the open forward end and the inner wall 9 a of the concavity 9parallel to the forward end, and count two in number to trisect thespace in the concavity 9 in this case. Three terminals 5 are disposed inthree sockets, respectively, defined by the projections 10 thus formedinside the concavity 9.

The projections 10 provided in the concavity 9 of the memory card 1 willprevent the user from inadvertently touching the terminals 5 wheninserting the memory card 1 into the receptacle. The terminals 5 can bethus protected.

The central one of the terminals 5 disposed in the three sockets definedby the projections 10 in the concavity 9 should desirably be connectedto the ground potential.

Since the memory card 1 is connected at the central one of the terminals5 to the ground potential, even when the user's finger is put into theconcavity 9, it will touch the grounded one of the terminals 5 so that astatic electricity, if any, caused by touching the terminals 5 with thefinger will be connected to the earth and thus the memory chip 3 willnot be damaged by the static electricity.

As shown in FIG. 4, the memory card 1 may have formed in the concavity 9a corresponding number of the projections 10 to a desired number of theterminals 5, and have the terminals 5 disposed in the sockets,respectively, defined by the projections 10 in the concavity 9. Theprojections 10 thus formed for the terminals 5 will positively preventthe terminals 5 being accessed or touched from outside.

It should be noted that ten terminals 10 may be provided in the memorycard 1 as shown in FIG. 1B. Three of these ten terminals 5 may bereserved ones. In the memory card 1 with such ten reserved terminals 5,the three reserved terminals 5 can be used as signal input or outputterminals to permit a parallel interface using a total of four signalinput or output terminals including the aforementioned digital signalinput/output terminal.

The present invention has been described in the foregoing concerning anembodiment in which the projections 10 are formed in the concavity toprevent access—or touch to the terminals 5. However, the memory card 1according to the present invention may comprise a shutter member 11which is moved to open or close the concavity 9. As shown in FIG. 5A,when the memory card 1 is not inserted in the receptacle, the shuttermember 11 closes the concavity 9 to prevent access to the terminals 5.In this embodiment, the card body 2 has formed therein, over an axialdistance substantially corresponding to the axial length of theconcavity 9 from the inner wall 9 a parallel to the forward end of theconcavity 9, an indentation in which the shutter member 11 is slidable.

The shutter member 11 is a rectangular plate made of a synthetic resin,for example, and slightly larger in area than the top opening of theconcavity 9, and it is installed at the forward end of the card body 2to be movable in the inserting direction. While the memory card 1 is notinserted in the receptacle, the shutter member 11 is pressed to theforward end of the concavity 9 to cover the top opening of the concavity9.

When the memory card 1 is inserted into the receptacle, it will abut atthe forward end thereof on projections of the receptacle as will befurther described later. As shown in FIG. 5B, as the memory card 1 isinserted, the shutter member 11 is pushed in by the projections againstthe force of a spring member 12 in the direction of arrow B, and movedinto the above-mentioned indentation so that the concavity 9 will beopen at the top thereof.

When the memory card 1 is not inserted into the receptacle, theconcavity 9 is covered by the shutter member 11, so that the terminals 5are prevented from being accessed or touched from outside and thusprotected.

In the memory card 1 according to this embodiment as well, the innerwall 9 a parallel to the forward open end of the concavity 9 is inclinedat a predetermined angle with respect to the bottom 9 b. Also theshutter member 11 should desirably have an inclined forward end face.

The memory card 1 has thus the inclined inner wall 9 a parallel to theforward open end of the concavity 9 and the inclined forward end face ofthe shutter member 11 so that when the memory card 1 is inserted intothe receptacle, dust or the like in the concavity 9 can easily be letout from on the inclined wall and end face.

Also in this memory card 1, the projections 10 may be formed inside theconcavity 9 to define sockets for the terminals 5 as shown in FIGS. 6Aand 6B. Thus, the projections 10 can positively protect the terminals 5by preventing touch to them even when the shutter member 11 isinadvertently opened with the memory card 1 not yet inserted into thereceptacle. FIG. 6A shows the top opening of the concavity 9 beingcovered or closed by the shutter member 11 while FIG. 6B shows theshutter member 11 moved away from on the concavity 9 and thus theconcavity 9 being open at the top thereof.

FIGS. 7 and 8 show a memory card receptacle, generally indicated with areference 20, adapted to receive the memory card 1 having been describedin the foregoing. When the memory card 1 constructed as in the above isused, it is inserted in the receptacle 20 as shown in FIGS. 7 and 8 torecord or reproduce information signal into or from the memory card 1.

As shown, the memory card receptacle 20 has an opening 21 formed at thefront end thereof, through which the memory card 1 is inserted into thereceptacle 20. Also, the receptacle 20 has formed therein, in theinserting direction of the memory card 1 indicated with an arrow C inFIG. 7, a memory card receiving concavity 22 axially extending from theopening 21 to a depth in the receptacle 20 and in which the memory card1 is received. There are disposed inside this memory card receivingconcavity 22 tips of a plurality of terminals 23 electrically connectedto an external system as shown in FIG. 7.

The terminals tips 23 are formed by punching a thin metal sheet, forexample. The terminals 23 are supported with the bases thereof buried inthe body of the receptacle 20 as shown. Therefore, the terminals 23 alsowork as leaf springs which depress the terminals 5 of the memory card 1inserted in the receptacle 20. The terminals 23 have each a contactpoint 23 aformed near the free ends thereof inside the receivingconcavity 22 and which are put into contact with the terminals 5 of thememory card 1.

The terminals 23 of the receptacle 20 are equal in number to theterminals 5 of the memory card 1. In this embodiment of the receptacle20, nine terminals 23 for the nine terminals 5 of the memory card 1 areprovided in the receiving concavity 22.

Further, there are provided ahead of the terminals 23 disposed in thereceiving concavity 22, that is to say, in positions corresponding tothe forward end of the memory card 1 when inserted in the receptacle 20,projections 24 which will slide on the terminals 5 of the memory card 1when the latter is inserted into the receptacle 20. The projections 24are equal in number to the terminals 5 of the memory card 1 similarly tothe terminals 23 of the receptacle 20. The projections 24 are providedahead of the terminals 23. In this embodiment of the receptacle 20, nineprojections 24 are thus provided for the nine terminals 5. When thememory card 1 is inserted into the receptacle 20, the projections 24slide on the terminals 5 of the memory card 1 before they get intocontact with the terminals 23 as shown in FIG. 9. The projections 24will let out dust or the like from inside the concavity 9 of the memorycard 1 over the inclined wall 9 a of the concavity 9 of the memory card1.

When the memory card 1 is inserted into the memory card receptacle 20,the projections 24 move ahead of the terminals 23 and slide on theterminals 5 of the memory card 1. After the projections 24 let out dustor the like from on the terminals 5, the terminals 23 get into contactwith the terminals 5 of the memory card 1. Thus, the terminals 23 and 5are electrically connected to one another in a positive manner.

In the receptacle 20, the plurality of projections 24 is provided aheadof the terminals 23 correspondingly to the terminals 5, respectively, ofthe memory card 1 in such a manner that the projections 24 can be wellfitted into the sockets defined by the projections 10 inside theconcavity 9 of the memory card 1 for the respective terminals 5. Thus,the receptacle 20 can suitably receive the memory card 1 of such astructure as well as the memory card 1 having the concavity 9 of whichthe space is similarly trisected by the projections 10.

Further, the receptacle 20 can well receive the memory card 1 having theconcavity 9 of which the top opening can be covered by the shuttermember 11 for protection of the terminals 5. In this example, when thememory card 1 having the shutter member 11 is inserted into thereceptacle 20, the projections 24 abut at the front end faces thereof onthe forward end of the shutter member 11 which will thus be moved openas the memory card 1 is further inserted into the receptacle 20, as seenfrom FIG. 10.

Also it is of course that the receptacle 20 can receive a memory cardhaving only the concavity 9 formed at the forward end, in the insertingdirection, of the card body 2, and the terminals 5 disposed in theconcavity 9, as shown in FIG. 11, with the projections 10 and shuttermember 11 not provided.

The memory card receptacle 20 is versatile as having been described inthe above, namely, it can be universally applied without beingrestricted by the shape of the memory card 1

It should now be noted that the memory card according to the presentinvention may also be constructed as will be discussed below:

FIG. 12 is a plan view of an example of the memory card, and FIG. 13 isa sectional view taken along the line X₁-X₂ of the memory card in FIG.12.

The memory card is generally indicated with a reference 100. It has agenerally rectangular flat shape having four corners 101 a, 101 b, 101 cand 102. Of these four corners, one (101 a) of the corners at theforward end, in the inserting direction, of the memory card 100indicated with the arrow D, and both the corners 101 b and 110 c at therear end, in the inserting direction of, the memory card 100 indicatedwith the arrow D, are chamfered much more than the remaining corner, orthe latter is not chamfered. Namely, the memory card 100 is so shapedthat it can be judged based on the position of the corner 102 whetherthe memory card 100 being inserted into the receptacle is positionedcorrectly or incorrectly, whereby the memory card 100 can be preventedfrom incorrectly being inserted into the receptacle.

As mentioned above, the remaining corner 102 at the forward end, in theinserting direction, of the memory card 100 indicated with the arrow Dis not chamfered while the other three corners 101 a, 101 b and 101 care chamfered to have an arcuate form, for example. Furthermore, thecorner 101 a is rounded much more than the other two corners 101 b and101 c as shown in FIG. 12.

When used for information recording or reproduction, the memory card 100is inserted into a receptacle 103 as shown in FIGS. 14 and 15. FIG. 14is a plan view of an example of the receptacle 103, and FIG. 15 is asectional view taken along the line Y₁-Y₂ of the receptacle 103 in FIG.14. Although FIG. 14 is a plan view, hatching is made somewhere thereinfor better understanding of the relation between the members of thereceptacle 103.

The receptacle 103 has formed at the forward end thereof an opening 104through which the memory card 100 is to be inserted, formed therein areceiving concavity 105 extending from the opening 104 along theinserting direction of the memory card 100 indicated with an arrow E,and provided at the innermost portion of the opening 104 an incorrectinsertion-preventive member 106 extending in the inserting direction ofthe memory card 100 indicated with the arrow E.

The incorrect insertion-preventive member 106 has at the opening 104 ofthe receptacle 103 a front end face 107 extending generallyperpendicular to the inserting direction of the memory card 100, and aprojection 108 formed at one of the lateral ends of the front end face107. The projection 108 has an oblique surface 109 which becomes thinnerand narrower as it goes from the front end face 107 toward the opening104. The oblique surface 109 detects the corner 102 of the memory card100.

Further the incorrect insertion-preventive member 106 is pivoted andforced clockwise in the plane of FIG. 15 under the action of a coilspring 110. When the receptacle 103 is not used, the member 106 closesthe opening 104 to block dust or the like from coming into thereceptacle 103.

FIGS. 16, 17 and 18 show the memory card 100 correctly inserted in thereceptacle 103. As the memory card 100 is inserted from the opening 104in the direction of arrow E, it will abut at the corner 102 thereof onthe projection 108 formed on the incorrect insertion-preventive member106 as shown in FIG. 16. Then the upper end of the corner 102 slides onthe oblique surface 109 of the projection 108 as shown in FIG. 17 andurges up the incorrect insertion-preventive member 106. Eventually thecorner 102 will allow the incorrect insertion-preventive member 106 toescape as shown in FIG. 18 and thus the memory card 100 is allowed to gointo place in the receptacle 103.

FIGS. 19 and 20 show the memory card 100 being inserted in a wrongdirection into the receptacle 103. As the memory card 100 is inserted inthe direction of arrow E, the rounded corner 101 a will not abut on theprojection 108 of the incorrect insertion-preventive member 106 but atthe forward end, in the inserting direction, thereof on the front endface 107 of the incorrect insertion-preventive member 106. Since thefront end face 107 of the member 106 is formed generally perpendicularto the inserting direction of the memory card 100 indicated with thearrow E, the forward end of the memory card 100 will be caught by theprojection 108 and thus cannot urge up the incorrectinsertion-preventive member 106. Therefore, if the memory card 100 isincorrectly inserted into the receptacle 103, the corner 101 a will notallow the incorrect insertion-preventive member 106 to escape, so thatthe memory card 100 cannot be inserted deep into place in the receptacle103.

FIGS. 19 and 20 show an example in which the memory card 100 is insertedupside down in the receptacle 103. Also in this case, the corners 101 band 101 c will not allow the incorrect insertion-preventive member 106to escape, so that the memory card 100 cannot be inserted deep intoplace in the receptacle 103. Therefore, it is only when the memory card100 is inserted correctly that the memory card 100 can be inserted deepinto place in the receptacle 103. Thus, the memory card 100 can beprevented from being incorrectly inserted into the receptacle 103.

For the purpose of preventing an incorrect insertion of the memory card100, the corners 101 a, 101 b and 101 c have only to be formed not toabut on the projection 108 of the incorrect insertion-preventive member106, and thus may be shaped to have any flat form. For example, thecorners may be chamfered in different sizes as well as in various shapessuch as arcuate, linear or the like as shown in FIG. 21. Such variationsin chamfered size and shape of the corners will also give a variation tothe memory card design.

Also it should be noted that the memory card according to the presentinvention may be constructed as will be discussed below:

FIG. 22 shows, in the form of a plan view, an example of the memorycard, and FIG. 23 is a sectional view taken along the line Z₁-Z₂ of thememory card shown in FIG. 22.

This memory card 120 is generally rectangular in shape, and cut at 121at the bottom edge of the forward end thereof in the inserting directionindicated with an arrow F as will be seen from FIG. 23. The cut 121extends over the entire forward-end short side of the memory card 120,and provides an oblique flat end face.

For preventing incorrect insertion of the memory card 120, it is judgedbased on the position of this cut 121 whether the memory card 120 isinserted correctly or incorrectly, as will be discussed below.

For information recording or reproduction, the memory card 120 isinserted into place in a receptacle 122 as shown in FIGS. 24 and 25.FIG. 24 is a plan view of an example of the construction of thereceptacle 122, and FIG. 25 is a sectional view taken along the lineW,-W₂ of the receptacle 122 shown in FIG. 24. The receptacle 122 hasformed at the forward end thereof an opening 123 through which thememory card 120 is to be inserted, formed therein a receiving concavity124 extending from the opening 123 in the inserting direction of thememory card 120 indicated with an arrow G, and provided at the innermostportion of the opening 123 an incorrect insertion-preventive member 125extending in the inserting direction of the memory card 120 indicatedwith the arrow G.

As shown in FIG. 25, the incorrect insertion-preventive member 125 has ablocking plate 127 having a first face 126 generally perpendicular tothe inserting direction of the memory card 120 indicated with the arrowG, and a projection 129 provided at the upper end of the blocking plate127 on the side of the opening 123 and which has a second face 128generally parallel to the inserting direction of the memory card 120.

Further the incorrect insertion-preventive member 125 is pivoted andforced clockwise in the plane of FIG. 25 under the action of a coilspring 130. When the receptacle 122 is not used, the member 125 closesthe opening 123 to block dust or the like from coming into thereceptacle 122.

As the memory card 120 is inserted into the receptacle 122, theincorrect insertion-preventive member 125 is rotated about 90°counterclockwise (in the plane of Figure) against the action of the coilspring 130 and the first face 126 will be generally parallel to theinserting direction of the memory card 120.

When the memory card 120 is correctly inserted into the receptacle 122,that is to say, when the cut 121 formed at the bottom edge of theforward end of the memory card 120 is positioned down, the forward endof the memory card 120 will slide at the oblique face of the cut 121onto the projection 129 to depress the incorrect insertion-preventivemember 125, as shown in FIG. 26. Thus, the cut 121 will allow theincorrect insertion-preventive member 106 to escape as shown in FIG. 27and thus the memory card 120 is allowed to go deep into place in thereceptacle 122.

When the memory card 120 is inserted in a wrong direction into thereceptacle 122, that is, when the cut 121 is not positioned down asshown in FIG. 28, the memory card 120 will abut at the forward endthereof onto the second face 128 of the projection 129. Since the secondface 128 is generally perpendicular to the inserting direction of thememory card 120 indicated with the arrow G, the forward end of thememory card 120 is caught by the projection 129 so that it cannotdepress the incorrect insertion-preventive member 125. Therefore, whenthe memory card 120 is inserted in a wrong direction, the incorrectinsertion-preventive member 125 cannot be allowed to escape to insertthe memory card 120 deep into place in the receptacle 122.

FIG. 28 shows the memory card 120 being inserted upside down into thereceptacle 122. Also when the memory card 120 is inserted in a reversedirection, the incorrect insertion-preventive member 125 cannot beallowed to escape to insert the memory card 120 deep into place in thereceptacle 122. Therefore it is only when the memory card 120 isinserted correctly that it can be inserted deep into place in thereceptacle 122. Thus, it is possible to prevent incorrect insertion ofthe memory card 120.

Since it is judged based on the shape in the direction of the width ofthe memory card 120 whether the memory card 120 is inserted correctly orincorrectly, the cut 121 has only to be formed to a size over which theprojection 129 can be slid to depress the incorrect insertion-preventivemember 125. Therefore, for the purpose of preventing an incorrectinsertion of the memory card 120, the corners thereof has only to beshaped to have any flat form. For example, the memory card 120 may bechamfered at the corners thereof in different sizes as well as invarious shapes such as arcuate, linear or the like, as shown in FIG. 29.Such variations in chamfered size and shape of the corners will alsogive a variation to the memory card design.

In addition to the above-mentioned structure designed for insertion intothe receptacle, the memory card according to the present invention maybe designed for fitting onto the top of the receptacle

FIG. 30 shows an example of the memory card of such design. In thiscase, the memory card is generally indicated with a reference 140. FIG.31 is a view of the memory card 140 from a direction H in FIG. 30, andFIG. 32 is a view of the memory card 140 from a direction I in FIG. 30.The memory card 140 has a generally rectangular flat shape. Also thememory card 140 has recesses 143 a and 143 b formed at end portions,respectively, of a first longitudinal side 141 thereof and also recesses143 c and 143 d formed at end portions, respectively, of a secondlongitudinal side 142 parallel to the first longitudinal side, as shownin FIG. 31.

The memory card 140 can be fitted into a receptacle 144 using therecesses 143 a to 143 d thereof as will be described below.

As shown in FIG. 33, the receptacle 144 has formed on the top thereof aconcavity 145, for example, in which the memory card 140 is to befitted. The concavity 145 is open at the top thereof, and projections146 are formed on side walls, respectively, of the concavity 145. Forexample, the memory card 140 can be fitted to the receptacle 144 withthe projections 146 of the receptacle 144 engaged in the recesses 143(143 a to 143 d) of the memory card 140, as shown in FIG. 34.

The memory card 140 can be directly set in a recording/reproducingapparatus. Also, the memory card 140 may be fitted in an adapter havinga shape of a flexible disk, PC card or the like, for example, and thenthe adapter in which the memory card 140 is fitted be set in therecording/reproducing apparatus.

In this case, since the memory card is fitted in a receptacle and thenset in the recording/reproducing apparatus, the top cover of thereceptacle is unnecessary and the receptacle can be designed thinnerthan a one which is to receive the memory card therein so that thereceptacle can be designed more compact. Also, the above-mentionedadapter destined to have the memory card fitted therein for setting intoa recording/reproducing apparatus can be designed to have a reducedthickness.

FIG. 35 shows the use of the memory card for storing data from a hostcomputer. It should be noted that an embodiment will be explained forthe case of writing video data transmitted from the host computer, onthe memory card, but the present invention can also be applied to dataother than video data such as audio data.

As shown in FIG. 35, the aforementioned host computer 201 includes: ahard disc 211 for storing various data such as video data of a stillimage data and audio data; a RAM (random access memory) 212 fortemporarily storing and reading out the video data and other data fromthe hard disc 211; a display interface (hereinafter referred to as adisplay I/F) 213; a display 214 for displaying an image according to thevideo data supplied via the display interface 213; a serial interface(hereinafter, referred to as a serial I/F) 215 for transmitting andreceiving data to/from a memory card 202 via three data lines; a bus216; and a CPU (central processing unit) 217 for control.

The RAM 212, for example, temporarily stores video data stored in thehard disc 211 via the bus 216 and, when necessary, supplies the videodata via the bus 216 to the serial I/F 215.

The display 214 is supplied via the bus 216 and the display I/F 213 withthe video data which has been read out from the hard disc 211 or videodata from the memory card 202, so that a still image or a moving pictureis displayed according to the supplied video data.

The serial I/F transmits data to the memory card 202 or receives datastored in the memory card in serial form via the three data lines. Morespecifically, via a first data line, the serial I/F 215 transmitsinformation data and control data for writing into the memory card 202and receives information data read out from the memory card. Via asecond data line, the serial I/F 215 outputs a state signal representingwhether information data or control data is supplied via the first dataline. Furthermore, via a third data line, the serial I/F 215 transmits aserial clock SCLK for transmission of the aforementioned control dataand video data.

The CPU 217 controls reading out of information data from the RAM 212and the hard disc 211 and writing information data into the RAM. The CPUalso controls transmission and reception of information data to/from thememory card 202. For example, the CPU 217 issues a register instructionto detect whether an erase prevention switch (which will be detailedlater) is in its ON state to prevent stored data from being erased oroverwritten, and issues to the memory card 202 a write instruction forwriting information data to an address.

As shown in FIG. 36, the memory card 202 includes: a control IC 221 forreceiving information data and control data from the aforementioned hostcomputer 201; a flash memory 222 for storing the information data; andan erase prevention switch 223 for preventing erroneous erasure of theinformation data stored in the flash memory 222.

As described previously, the memory card is provided with the control IC221, the flash memory 222, and the erase prevention switch 223. Theerase prevention switch may be provided at one end of the memory card,as shown in FIGS. 3 and 4, or may be provided on a surface of the memorycard as shown in FIG. 30. The erase prevention switch is slidable fromside-to-side. When the erase prevention switch is set to one side, writeprotection (or erasure prevention) is in the OFF state and data can berecorded. When the erase prevention switch 223 is set to the other side,the user is provided with an observable indicia representing that writeprotection (or erasure prevention) is in the ON state; and the memorycard 202 is disabled for recording data. Consequently, a user isprovided with an indication of the state of the memory card, even whenthe memory card is placed in the receptacle described above.

The control IC 221, prior to writing data from the host computer 201into the flash memory 222, detects whether the write protect state ofthe erase prevention switch 223 is ON or OFF. Data is written to theflash memory only when the write protect state is OFF.

Here, the control IC 221 includes: a serial/parallel-parallel/serialinterface sequencer (hereinafter, referred to as an S/P & P/S sequencer)213; a page buffer 232 for temporarily storing data from the SP & P/Ssequencer; a flash interface sequencer (hereinafter, referred to as aflash I/F sequencer) 233 for supplying the data from the page buffer232, to the flash memory 222; an ECC encoder/decoder 234 for carryingout error correction processing; a command generator 235 for generatinga predetermined control command; a configuration ROM (read only memory)236 containing version information as well as other information; and anoscillator 237 for supplying a clock to respective circuits.

The S/P & P/S sequencer 231 is connected via the aforementioned threedata lines to the serial I/F 215 of the host computer 201. Thus, the SIP& P/S sequencer 231 is supplied from the host computer with a statussignal and a serial clock SCLK as well as serial data DIO consisting ofvideo data (or other information data as may be supplied form the host)and control data.

The SIP & P/S sequencer 231 converts the serial data DIO supplied fromthe host computer into parallel data in synchronization with theaforementioned serial clock SCLK. Among the parallel data, for example,the SIP & P/S sequencer 231 supplies control data to the commandgenerator 235 and information data to the page buffer 232.

The page buffer is a buffer memory for storing the information datasupplied from the S/P & P/S sequencer 231 on a page (=512 bytes) basis.An error correction code produced by the ECC encoder/decoder 234 isadded to the data stored in the page buffer. The page buffer suppliesone page of data (to which the error correction code has been added) viathe flash I/F sequencer 233 to the flash memories 222 a to 222 d. Thus,the data from the host computer is written in the flash memories.

Similarly, the data read out from the flash memories is supplied via theflash I/F sequencer 233 to the page buffer 232 which stores such data.Here, the ECC encoder/decoder 234 carries out an error correctionprocessing according to the error correction code added to the datastored in the page buffer 232. The error corrected data is read out fromthe page buffer page after page, and is supplied to the S/P & P/Ssequencer 231. The S/P & P/S sequencer converts the parallel datasupplied from the page buffer into serial data DIO for transmission tothe host.

The command generator 235 generates a control command according tocontrol data supplied from the S/P & P/S sequencer 231. For example,when the command generator receives a read status instruction (which isused to check the operation state of the memory card), the state of theerase prevention switch 223 is sensed and used to determine whether datashould be written to the memory card.

The command generator 235 also generates a busy command (hereinafter,referred to as a busy signal) indicating that data is being written tothe flash memory 222 or that data is being read from the flash memory.This busy command is supplied via the S/P & P/S sequencer 231 to thehost. When the writing or reading of data is complete, the commandgenerator generates a ready command (hereinafter, referred to as a readysignal) indicative thereof, and transmits the ready command via the S/P& P/S sequencer 231 to the host. The host recognizes the operation stateof the memory card in response to the busy signal and the ready signal.

The configuration ROM 236 contains version information and informationof an initial value of the memory card 202. When a connection is madebetween the host and the memory card, the command generator 235 firstreads out the version information from the configuration ROM via the S/P& P/S sequencer and generates a predetermined command according to thisinformation, thus executing predetermined initialization of the memorycard.

In the host and the memory card having the aforementioned configuration,when data from the host computer is written to the memory card as shownin FIG. 37, the host executes the operations of steps S1 to S8 while thememory card executes the operations of steps S11 to S14.

In the host, when data writing to the memory card is specified, the CPU217 issues a read status instruction to check the state of the memorycard (step S1) and transmits this instruction via the serial I/F 215 tothe memory card. This read status instruction is issued for and inadvance of each data file to be transmitted.

In the memory card, when the command generator 235 receives theaforementioned read status instruction via the S/P & P/S sequencer 231,the state of the erase prevention switch 223 is loaded to a register,and the contents of this register is transmitted via the S/P & P/Ssequencer 231 to the host (step S11). In other words, the commandgenerator detects whether the erase prevention switch is in its ONstate, i.e., whether write protect of the memory card is ON, sets thisstate in the register and transmits the register content to the host.

In the host, CPU 217, the register content supplied from the memory cardis used to determine whether write protect is ON (step S2) and, if so,the CPU 217 carries out write inhibit processing (step S3).

When the CPU 217 determines that write protect is not ON, the CPU issuesa write page buffer instruction and reads out data of 512 bytes from thehard disc 211, for example. The write page buffer instruction and thepage of data are supplied via the serial I/F 215 to the memory card(step S4).

Furthermore, the CPU issues a set command instruction and a writeinstruction including a write address for identifying the address atwhich the data is to be written on the memory card 202 (step S5). TheCPU transmits these command instructions via the serial I/F 215 to thememory card.

In the memory card, when the command generator 235 receives the setcommand instruction from the host via the S/P & P/S sequencer 231, thecommand generator sets a busy state in the aforementioned register andtransmits a busy signal representing this register content via the S/P &P/S sequencer 231 to the host (step S12). It should be noted that thisbusy signal is repeatedly transmitted to the host until the ready stateis set in the register by the command generator.

Then, the command generator issues a write command to write one page ofthe data into the aforementioned identified address of the flash memory222 (step S13). When the writing of the one page of data is complete,the command generator 235 sets a ready state in the register andtransmits a ready signal representing this register content via the S/P& P/S sequencer to the host computer (step S14).

At this time, the CPU 217 in the host terminates the set commandinstruction (step S5) and issues a read status instruction to check thestate of the memory card 202 (step S6). The CPU 217 senses whether thesignal transmitted from the memory card via the serial I/F 205 is a busysignal. If it is, the CPU again issues the read status instruction (stepS6). That is, while the busy signal is transmitted from the memory card,the CPU cycles through steps S6 and S7.

When the CPU 217 senses that the signal transmitted from the memory cardis not a busy signal, i.e., that the signal transmitted is a readysignal, the CPU determines whether more data is to be transmitted to thememory card. If so, control is passed to step S4; and if no further datais to be transmitted, the data transmission processing is terminated(step S8). That is, a file data to be recorded is written on a pagebasis into the memory card by repeating the processing of steps S4 to S8and the processing of steps S12 to S14 until the file is written.

As has been described above, the ON/OFF state for write protect of thememory card is determined for each file recording. Consequently, if thewrite protect state of the erase prevention switch 223 is changed whilethe memory card 2 is mounted on or in the host computer, the writing ofdata may be inhibited, depending upon the state of this switch. Sincethe state of the erase prevention switch 223 can be changed while thememory card is mounted on the host computer, there is no need to removethe memory card from the host in order to switch the erase preventionswitch, thus improving operability for the user.

Next is described the operation of erasing data stored in the memorycard 202. When erasing data, the host carries out the processingrepresented by steps S21 to S27 while the memory card carries out theprocessing represented by steps S31 to S34, as shown in FIG. 38.

In the host, when data stored in the memory card is to be erased, theCPU 217 issues a read status instruction (step S21) so as to check thestate of the memory card, and this read status instruction istransmitted via the serial I/F 215 to the memory card 202. It should benoted that this read status instruction is issued for each of the filesto be erased.

In the memory card, when the command generator 235 receives the readstatus instruction, the command generator loads the state of the eraseprevention switch 223 into the aforementioned register, and transmitsthe register content via the S/P & P/S sequencer 231 to the hostcomputer (step S31). In other words, the command generator loads theregister with the ON or OFF write protect state of the memory card andtransmits this register content to the host.

In the host, the CPU 217 determines whether the write protect is ON,based upon the register content transmitted from the memory card (stepS22) and if write protect is ON, data erasure is inhibited (step S23).

If write protest is OFF, the CPU issuses a set command instrction andissuses an erase instruction (step S24) to erase the data stored in aspecified address in the memory card. The CPU transmits theseinstructions via the serial I/F 215 to the memory card.

In the memory card, upon receipt of the aforementioned set commandinstruction from the host, the command generator 235 transmits a busysignal via the S/P & P/S sequencer 231 to the host (step S32). Thecommand generator also issues a command to erase the data stored in thespecified address in the flash memory 222 (step S33). It should be notedthat in the flash memory, the data is erased for each block consistingof a predetermined number of sets of one-page (512 bytes) data and18-bytes management information.

When data erasure is complete, the command generator 235 loads a readystate in the register and transmits a ready signal representing theregister content via the S/P & P/S sequencer 231 to the host (step S34).

At the host, the CPU 217 terminates the set command instruction producedin step S24, and then issues a read status instruction to check thestate of the memory card (step S25). The CPU 217 senses whether thesignal transmitted from the memory card via the serial I/F 215 is a busysignal, and if it is, the read status instruction is again issued (stepS26). Consequently, while the busy signal is transmitted from the memorycard, the CPU cycles through steps S25 and S26.

When the CPU 217 senses that the signal transmitted form the memory cardis not a busy signal, i.e., the signal transmitted is a ready signal,the CPU determines whether more data is to be erased from the memorycard. If so, control is passed to step S24; and if no further data is tobe erased, the data erase processing is terminated (step S27). That is,the file of data to be erased is erased on a block basis by repeatedlycarrying out the processing represented by steps S24 to S27 and stepsS32 to S34.

As has been described, the ON/OFF state of write protect of the memorycard is checked for each file to be erased, and if the write protectstate is changed by switching the erase prevention switch 223 while thememory card is mounted on the host, the erasing of data may beinhibited, depending upon the state of the switch.

It should be noted that the present invention is not to be limited tothe particular embodiment described above, but can be modified withoutdeparting from the scope of the invention. For example, the slidableerase prevention switch can be provided at one end of the rectangularcard body, as shown in FIG. 3, or it may be provided on the surface ofthe card body, as shown in FIG. 30.

In one application of the present invention, the information data isvideo data. In another application, the information data is audio dataand the host is, for example, a digital voice or music recorder orplayback device. In yet another application, the information data isreceived from a data distribution network, such as the internet, and maybe, for example, electronic music data, video data, text data, or thelike. Here, the host may be interface apparatus connectable to thenetwork. In a further application the information data is image data andthe host is a portable scanner for producing such image data.

What is claimed is:
 1. A memory card for storing data written theretofrom an external device, comprising: a substantially rectangular cardbody having first and second substantially rectangular surfaces andedges between said surfaces; terminals provided in the vicinity of oneof the edges between said surfaces and on said first substantiallyrectangular surface for inputting data from or outputting data to saidexternal device; a storage device disposed in said card body for storingsaid data inputted from said terminals; an electric switch located onsaid first substantially rectangular surface and operable to a state toprevent the data stored in said storage device from being erased; and acontrol circuit disposed within said card body and electricallyconnected between said terminals and said storage device for writingdata from an external device to said storage device, for reading outstored data to said terminals from said storage device and for supplyingto said terminals a status signal representing the state of said switch;said switch being disposed proximate said terminals and electricallyconnected to said control circuit.
 2. The memory card of claim 1 whereinsaid switch has a slide member located in a recess disposed on said onesurface.
 3. The memory card of claim 2 wherein said switch isreciprocally movable in a side-to-side manner toward one and away fromthe other of longitudinal ones of said edges, the state of said switchbeing determined by the position thereof.
 4. A memory card for storingdata written thereto from an external device, comprising: asubstantially rectangular card body having first and secondsubstantially rectangular surfaces and edges between said surfaces;terminals provided in the vicinity of one of the edges between saidsurfaces and on said first substantially rectangular surface forinputting data from or outputting data to said external device; astorage device disposed in said card body for storing said data inputtedfrom said terminals; an electric switch located on said firstsubstantially rectangular surface and operable to a state to prevent thedata stored in said storage device from being erased; and a controlcircuit disposed within said card body and electrically connectedbetween said terminals and said storage device for writing data from anexternal device to said storage device, for reading out stored data tosaid terminals from said storage device and for supplying to saidterminals a status signal representing the state of said switch, whereinsaid control circuit is responsive to a read status instruction signalfrom said external device to supply said status signal to saidterminals; said switch being disposed proximate said terminals andelectrically connected to said control circuit.
 5. The memory card ofclaim 4 wherein said control circuit is responsive to a writeinstruction signal from said external device to write data to saidstorage device; and wherein said read status instruction signal precedessaid write instruction signal. 6.The memory card of claim 4 wherein saidcontrol circuit is responsive to an erase instruction signal from saidexternal device to erase data stored in said storage device; and whereinsaid read status instruction signal precedes said erase instructionsignal.
 7. The memory card of claim 4 wherein said data written to saidstorage device comprises a data file; and wherein said read statusinstruction signal is supplied prior to writing a data file to orerasing a data file from said storage device.
 8. The memory card ofclaim 1 wherein said switch is operable while said memory card is usedwith said external device.
 9. The memory card of claim 1 wherein saidcontrol circuit receives signals from and transmits signals to saidexternal device in serial form.
 10. A memory card for storing datawritten thereto from an external device, comprising: a substantiallyrectangular card body having first and second substantially rectangularsurfaces and edges between said surfaces; terminals provided in thevicinity of one of the edges between said surfaces and on said firstsubstantially rectangular surface for inputting data from or outputtingdata to said external device; a storage device disposed in said cardbody for storing said data inputted from said terminals; an electricswitch located on one of the edges between said surfaces and operable toa state to prevent the data stored in said storage device from beingerased; and a control circuit disposed within said card body andelectrically connected between said terminals and said storage devicefor writing data from an external device to said storage device, forreading out stored data to said terminals from said storage device andfor supplying to said terminals a status signal representing the stateof said switch, said control circuit being responsive to a read statusinstruction signal from said external device to supply said statussignal to said terminals; and said switch being electrically connectedto said control circuit.
 11. The memory card of claim 10 wherein saidswitch has a slide member located in a recess disposed on said one edge.12. The memory card of claim 10 wherein said control circuit isresponsive to a write instruction signal from said external device towrite data to said storage device; and wherein said read statusinstruction signal precedes said write instruction signal.
 13. Thememory card of claim 10 wherein said control circuit is responsive to anerase instruction signal from said external device to erase data storedin said storage device; and wherein said read status instruction signalprecedes said erase instruction signal.
 14. The memory card of claim 10wherein said data written to said storage device comprise a data file;and wherein said read status instruction signal is supplied prior towriting a data file to or erasing a data file from said storage device.15. The memory card of claim 10 wherein said switch is operable whilesaid memory card is used with said external device.
 16. The memory cardof claim 10 wherein said control circuit receives data from andtransmits data to said external device in serial form.
 17. A systemcomprising: a memory card for storing data written thereto from anexternal device, including: a substantially rectangular card body havingfirst and second substantially rectangular surfaces and edges betweensaid surfaces; terminals provided in the vicinity of one of the edgesbetween said surfaces and on said first substantially rectangularsurface for inputting data from or outputting data to said externaldevice; a storage device disposed in said card body for storing saiddata inputted from said terminals; an electric switch located on saidfirst substantially rectangular surface and operable to a state toprevent the data stored in said storage device from being erased; and acontrol circuit disposed within said card body and electricallyconnected between said terminals and said storage device for writingdata from an external device to said storage device, for reading outstored data to said terminals from said storage device and for supplyingto said terminals a status signal representing the state of said switch;said switch being disposed proximate said terminals and electricallyconnected to said control circuit; and host apparatus for receiving andcommunicating with said memory card, said host apparatus including:terminals for transmitting signals to and reading this signals from saidmemory card; and a control circuit electrically connected to theterminals of said host apparatus for writing information to said memorycard and for receiving from said terminals of said host apparatus astatus signal representing the state of said switch on said memory card.18. The system of claim 17 wherein said switch has a slide memberlocated in a recess disposed on said one surface.
 19. The system ofclaim 18 wherein said switch is reciprocally movable in a side-to-sidemanner toward one and away from the other of longitudinal ones of saidedges, the state of said switch being determined by the positionthereof.
 20. A system comprising: a memory card for storing data writtenthereto from an external device, including: a substantially rectangularcard body having first and second substantially rectangular surfaces andedges between said surfaces; terminals provided in the vicinity of oneof the edges between said surfaces and on said first substantiallyrectangular surface for inputting data from or outputting data to saidexternal device; a storage device disposed in said card body for storingsaid data inputted from said terminals; an electric switch located onsaid first substantially rectangular surface and operable to a state toprevent the data stored in said storage device from being erased; and acontrol circuit disposed within said card body and electricallyconnected between said terminals and said storage device for writingdata from an external device to said storage device, for reading outstored data to said terminals from said storage device and for supplyingto said terminals a status signal representing the state of said switch,wherein said control circuit is responsive to a read status instructionsignal from said external device to supply said status signal to saidterminals; said switch being disposed proximate said terminals andelectrically connected to said control circuit; and host apparatus forreceiving and communicating with said memory card, said host apparatusincluding: terminals for transmitting signals to and reading thissignals from said memory card; and a control circuit electricallyconnected to the terminals of said host apparatus for writinginformation to said memory card and for receiving from said terminals ofsaid host apparatus a status signal representing the state of saidswitch on said memory card.
 21. The system of claim 20 wherein saidcontrol circuit is responsive to a write instruction signal from saidexternal device to write data to said storage device; and wherein saidread status instruction signal precedes said write instruction signal.22. The system of claim 20 wherein said control circuit is responsive toan erase instruction signal from said external device to erase datastored in said storage device; and wherein said read status instructionsignal precedes said erase instruction signal.
 23. The system of claim20 wherein said data written to said storage device comprises a datafile; and wherein said read status instruction signal is supplied priorto writing a data file to or erasing a data file from said storagedevice.
 24. The system of claim 17 wherein said switch is operable whilesaid memory card is used with said external device.
 25. The system ofclaim 17 wherein said control circuit receives signals from andtransmits signals to said external device in serial form.
 26. A systemcomprising: a memory card for storing data written thereto from anexternal device, including: a substantially rectangular card body havingfirst and second substantially rectangular surfaces and edges betweensaid surfaces; terminals provided in the vicinity of one of the edgesbetween said surfaces and on said first substantially rectangularsurface for inputting data from or outputting data to said externaldevice; a storage device disposed in said card body for storing saiddata inputted from said terminals; an electric switch located on one ofthe edges between said surfaces and operable to a state to prevent thedata stored in said storage device from being erased; and a controlcircuit disposed within said card body and electrically connectedbetween said terminals and said storage device for writing data from anexternal device to said storage device, for reading out stored data tosaid terminals from said storage device and for supplying to saidterminals a status signal representing the state of said switch, saidcontrol circuit being responsive to a read status instruction signalfrom said external device to supply said status signal to saidterminals; and said switch being electrically connected to said controlcircuit; and host apparatus for receiving and communicating with saidmemory card, said host apparatus including: terminals for transmittingsignals to and reading this signals from said memory card; and a controlcircuit electrically connected to the terminals of said host apparatusfor writing information to said memory card and for receiving from saidterminals of said host apparatus a status signal representing the stateof said switch on said memory card.
 27. The system of claim 26 whereinsaid switch has a slide member located in a recess disposed on said oneedge.
 28. The system of claim 26 wherein said control circuit isresponsive to a write instruction signal from said external device towrite data to said storage device; and wherein said read statusinstruction signal precedes said write instruction signal.
 29. Thesystem of claim 26 wherein said control circuit is responsive to anerase instruction signal from said external device to erase data storedin said storage device; and wherein said read status instruction signalprecedes said erase instruction signal.
 30. The system of claim 26wherein said data written to said storage device comprise a data file;and wherein said read status instruction signal is supplied prior towriting a data file to or erasing a data file from said storage device.31. The system of claim 26 wherein said switch is operable while saidmemory card is used with said external device.
 32. The system of claim26 wherein said control circuit receives data from and transmits data tosaid external device in serial form.